A handheld bioprinter for multi-material printing of complex constructs.

In situbioprinting-the process of depositing bioinks at a defected area, has recently emerged as a versatile technology for tissue repair and restorationviasite-specific delivery of pro-healing constructs. The ability to print multiple materialsin situis an exciting approach that allows simultaneous or sequential dispensing of different materials and cells to achieve tissue biomimicry. Herein, we report a modular handheld bioprinter that deposits a variety of bioinksin situwith exquisite control over their physical and chemical properties. Combined stereolithography 3D printing and microfluidic technologies allowed us to develop a novel low-priced handheld bioprinter. The ergonomic design of the handheld bioprinter facilitate the shape-controlled biofabrication of multi-component fibers with different cross-sectional shapes and material compositions. Furthermore, the capabilities of the produced fibers in the local delivery of therapeutic agents was demonstrated by incorporating drug-loaded microcarriers, extending the application of the printed fibers to on-demand, temporal, and dosage-control drug delivery platforms. Also, the versatility of this platform to produce biosensors and wearable electronics was demonstrated via incorporating conductive materials and integrating pH-responsive dyes. The handheld printer's efficacy in generating cell-laden fibers with high cell viability for site-specific cell delivery was shown by producing single-component and multi-component cell-laden fibers. In particular, the multi-component fibers were able to model the invasion of cancer cells into the adjacent tissue.

Increased Maximal Expiratory Pressure, Abdominal and Thoracic Respiratory Expansibility in Healthy Yoga Practitioners Compared to Healthy Sedentary Individuals

Abstract Background Increasing thoracic expansion is effective at reducing blood pressure in hypertensive subjects. Yoga prescribes many respiratory techniques with a growing number of practitioners. However, very little is known whether sedentary or yoga practitioners show measurable differences in their respiratory patterns. Objective This study aims to demonstrate differences between healthy sedentary individuals and healthy yoga practitioners regarding maximal respiratory pressures and thoracic and abdominal respiratory expansibility. Methods Maximal inspiratory and expiratory pressures (MIP and MEP, respectively) were evaluated by manovacuometry, while respiratory expansion was assessed by the cirtometry of abdominal (CA), thoracic xiphoidal (CTX), and thoracic axillary (CTA) circumferences at rest (end expiratory moment) and at full inspiration in healthy sedentary individuals (SED) and yoga practitioners (YOGA). A delta derived from rest and full inspiration measures (ΔCA, ΔCTX, and ΔCTA, respectively), followed by a percentage of each item (ΔCA/CA, ΔCTX/CTX, and ΔCTA/CTA) was then calculated. Groups were compared by means of an unpaired Student's t-test, with a significance level p < 0.05. Results All respiratory expansion measures were significantly higher in in the YOGA group. A significantly higher MEP (cmH2O) was also detected in yoga practitioners: SED 89.3 ± 19.3 and YOGA 114.7 ± 24.8 ( p = 0.007), along with decreased heart rate at rest (bpm): SED 84±6 and YOGA 74±15 ( p = 0.001). Conclusions Yoga practitioners have shown greater thoracic and abdominal expansion and increased MEP, when compared to healthy sedentary individuals, as well as significantly lower heart rates at rest and body mass index (BMI). However, whether or not these findings are related to respiratory patterns is uncertain.

Association of Bronchopulmonary Dysplasia and Right Ventricular Systolic Function in Young Adults Born Preterm.

BACKGROUND: Adults born preterm are at a higher risk of cardiopulmonary disease and premature death. Preterm birth is associated with abnormalities in right ventricular (RV) structure and function, but the impact of bronchopulmonary dysplasia (BPD), a common complication of extremely preterm birth, on these parameters remains unknown. RESEARCH QUESTION: Are preterm birth and BPD associated with alterations in RV structure and function in early adulthood? STUDY DESIGN AND METHODS: Echocardiographic and spirometry data were obtained from the Health of Adults Born Preterm Investigation (HAPI). RV structure and performance were evaluated by using echocardiography, and respiratory function was assessed by using spirometry. RESULTS: The study comprised 86 young adults born preterm before 30 weeks of gestation, including 28 with moderate to severe BPD, and 85 adults of the same age born full term. Individuals were assessed at a mean age of 23 years. RV systolic function was altered in the preterm group, with lower tricuspid annular plane systolic excursion and lower RV s' and RV outflow tract velocity time integral values, especially in those born preterm with BPD. Nine (36%) participants born preterm with BPD, six (13%) participants born preterm without BPD, and six (8%) participants born full term had a tricuspid annular plane systolic excursion value < 16 mm, a marker of RV systolic dysfunction (P value for the comparison between preterm no BPD and BPD, .032). No difference was found in RV diastolic function or estimates of pulmonary artery pressure between groups. Although respiratory function was altered in those born preterm, and more so in the case of BPD, no association was observed between spirometry indices of respiratory function and RV systolic function. INTERPRETATION: Preterm birth is associated in adulthood with alterations in RV systolic function, which are more pronounced in the case of BPD. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov; No.: NCT03261609; URL: www.clinicaltrials.gov.

Additional Improvement of Respiratory Technique on Vascular Function in Hypertensive Postmenopausal Women Following Yoga or Stretching Video Classes: The YOGINI Study.

Background: Hypertension remains highly prevalent in postmenopausal women, along with vascular dysfunction and increased oxidative stress. In such context, regular exercises, yoga practice, and slow breathing have been recommended to treat hypertension. However, the effects of the multiple components of yoga, including the respiratory techniques involved in the practice, on hypertension and on vascular and endothelial function have never been evaluated. Objective: This study aimed to investigate the additional effects of respiratory technique on vascular function and oxidative stress profile in hypertensive postmenopausal women (HPMWs) following yoga or stretching video classes. Study Design: Hypertensive postmenopausal women were recruited and randomized for 12 weeks, twice a week, of supervised yoga or stretching video classes of 75 min for 12 weeks associated or not with respiratory technique. Baseline and post-intervention measurements included pulse wave velocity (PWV), flow-mediated dilation (FMD), and oxidative stress parameters. Hypertensive postmenopausal women (59 ± 0.7 years) who ended the protocol were distributed into three groups: (1) control group (yoga or stretching, C, n = 14); (2) yoga + respiratory technique (Y+, n = 10); (3) stretching + respiratory technique (S+, n = 9). Results: Diastolic blood pressure and FMD [baseline: C: 6.94 ± 1.97%, Y+: 7.05 ± 1.65%, and S+: 3.54 ± 2.01% vs. post: C: 16.59 ± 3.46% (p = 0.006), Y+: 13.72 ± 2.81% (p = 0.005), and S+: 11.79 ± 0.99% (p = 0.0001)] have significantly increased in all groups when baseline and post-practice values were compared. However, resting heart rate and PWV [baseline: Y+: 10.44 ± 3.69 and S+: 9.50 ± 0.53 m/s vs. post: Y+: 9.45 ± 0.39 (p = 0.003) and S+: 8.02 ± 0.47 m/s (p = 0.003)] decreased significantly only in the Y+ and S+ groups (baseline vs. post). Systemic antioxidant enzyme activities (superoxide dismutase and catalase) increased in all groups, and hydrogen peroxide and lipoperoxidation reduced in Y+ and S+ (baseline vs. post). Conclusions: Twelve weeks of yoga or stretching video classes promoted positive changes in several outcomes generally regarded as cardiovascular risk factors in HPMWs, and these changes were even more pronounced by the association with respiratory technique.

Impact of early life AT1 blockade on adult cardiac morpho-functional changes and the renin-angiotensin system in a model of neonatal high oxygen-induced cardiomyopathy.

We previously reported that neonatal blockade of angiotensin II AT1 receptor prevents cardiac changes in 4 weeks rats with neonatal hyperoxia-induced cardiomyopathy, a recognized model of prematurity-related deleterious conditions. Considering the importance of AT1 receptor and the renin angiotensin system (RAS) in normal development, the present study aimed to investigate the adult effects of neonatal AT1 blockade on left ventricle (LV) in rats exposed to neonatal hyperoxia. Sprague-Dawley pups were exposed to 80% O2 or room air from days 3-10. AT1 blocker (losartan) or H2O were given by gavage from day 8-10. LV function (echo and intraventricular pressure), histology and expression of RAS components were examined in 15-16 weeks old adult males. Losartan treatment prevented myocardial fibrosis, LV wall thickening and stroke volume reduction in rats exposed to high O2 in the neonatal period. However, Losartan treatment of O2-exposed pups led to reduced ejection fraction (EF) and fractional shortening (FS), and did not prevent changes in diastolic function. Losartan also did not prevent increased LV AT2 and decreased angiotensin-(1-7) Mas receptors expression observed in high O2-exposed rats. Neonatal Losartan attenuated long-term impact of neonatal hyperoxia but also led to decreased EF and FS. Increased AT2 and decreased Mas receptor expression observed in O2-exposed group were unaffected by Losartan treatment. Our results show that early life Losartan treatment aimed at preventing cardiac consequences of neonatal deleterious conditions may also comprise detrimental effects that require further investigation prior to clinical translation in developing children.

Optimization of Vagal Stimulation Protocol Based on Spontaneous Breathing Rate.

Controlled breathing maneuver is being widely applied for cardiovascular autonomic control evaluation and cardiac vagal activation through reduction of breathing rate (BR). However, this maneuver presented contradictory results depending on the protocol and the chosen BR. These variations may be related to the individual intrinsic profile baseline sympathetic tonus, as described before by others. In this study, we evaluated the effect of controlled breathing maneuver on cardiovascular autonomic control in 26 healthy subjects allocated into two protocols: (1) controlled breathing in three different rates (10, 15, and 20 breaths/min) and (2) controlled breathing in rates normalized by the individual spontaneous breathing rate (SBR) at 100, 80, 70, and 50%. Our results showed autonomic responses favorable to vagal modulation with the lower BR maneuvers. Nevertheless, while this activation was variable using the standard protocol, all participants of the normalized protocol demonstrated an increase of vagal modulation at 80% BR (HFnu 80 = 67.5% vs. 48.2%, p < 0.0001). These results suggest that controlled breathing protocols to induce vagal activation should consider the SBR, being limited to values moderately lower than the baseline.

ACE gene dosage determines additional autonomic dysfunction and increases renal angiotensin II levels in diabetic mice.

OBJECTIVES: The present study aimed to investigate cardiovascular autonomic modulation and angiotensin II (Ang II) activity in diabetic mice that were genetically engineered to harbor two or three copies of the angiotensin-converting enzyme gene. METHODS: Diabetic and non-diabetic mice harboring 2 or 3 copies of the angiotensin-converting enzyme gene were used in the present study. Animals were divided into 4 groups: diabetic groups with two and three copies of the angiotensin-converting enzyme gene (2CD and 3CD) and the respective age-matched non-diabetic groups (2C and 3C). Hemodynamic, cardiovascular, and autonomic parameters as well as renal Ang II expression were evaluated. RESULTS: Heart rate was lower in diabetic animals than in non-diabetic animals. Autonomic modulation analysis indicated that the 3CD group showed increased sympathetic modulation and decreased vagal modulation of heart rate variability, eliciting increased cardiac sympathovagal balance, compared with all the other groups. Concurrent diabetes and either angiotensin-converting enzyme polymorphism resulted in a significant increase in Ang II expression in the renal cortex. CONCLUSION: Data indicates that a small increase in angiotensin-converting enzyme activity in diabetic animals leads to greater impairment of autonomic function, as demonstrated by increased sympathetic modulation and reduced cardiac vagal modulation along with increased renal expression of Ang II.

ACE gene dosage determines additional autonomic dysfunction and increases renal angiotensin II levels in diabetic mice

OBJECTIVES: The present study aimed to investigate cardiovascular autonomic modulation and angiotensin II (Ang II) activity in diabetic mice that were genetically engineered to harbor two or three copies of the angiotensin-converting enzyme gene. METHODS: Diabetic and non-diabetic mice harboring 2 or 3 copies of the angiotensin-converting enzyme gene were used in the present study. Animals were divided into 4 groups: diabetic groups with two and three copies of the angiotensin-converting enzyme gene (2CD and 3CD) and the respective age-matched non-diabetic groups (2C and 3C). Hemodynamic, cardiovascular, and autonomic parameters as well as renal Ang II expression were evaluated. RESULTS: Heart rate was lower in diabetic animals than in non-diabetic animals. Autonomic modulation analysis indicated that the 3CD group showed increased sympathetic modulation and decreased vagal modulation of heart rate variability, eliciting increased cardiac sympathovagal balance, compared with all the other groups. Concurrent diabetes and either angiotensin-converting enzyme polymorphism resulted in a significant increase in Ang II expression in the renal cortex. CONCLUSION: Data indicates that a small increase in angiotensin-converting enzyme activity in diabetic animals leads to greater impairment of autonomic function, as demonstrated by increased sympathetic modulation and reduced cardiac vagal modulation along with increased renal expression of Ang II.

Improved cardiovascular autonomic modulation in transgenic rats expressing an Ang-(1-7)-producing fusion protein.

Angiotensin-(1-7) counterbalances angiotensin II cardiovascular effects. However, it has yet to be determined how cardiovascular autonomic modulation may be affected by chronic and acute elevation of Ang-(1-7). Hemodynamics and cardiovascular autonomic profile were evaluated in male Sprague-Dawley (SD) rats and transgenic rats (TGR) overexpressing Ang-(1-7) [TGR(A1-7)3292]. Blood pressure (BP) was directly measured while cardiovascular autonomic modulation was evaluated by spectral analysis. TGR received A-779 or vehicle and SD rats received Ang-(1-7) or vehicle and were monitored for 5 h after i.v. administration. In another set of experiments with TGR, A-779 was infused for 7 days using osmotic mini pumps. Although at baseline no differences were observed, acute administration of A-779 in TGR produced a marked long-lasting increase in BP accompanied by increased BP variability (BPV) and sympathetic modulation to the vessels. Likewise, chronic administration of A-779 with osmotic mini pumps in TGR increased heart rate, sympathovagal balance, BPV, and sympathetic modulation to the vessels. Administration of Ang-(1-7) to SD rats increased heart rate variability values in 88% accompanied by 8% of vagal modulation increase and 18% of mean BP reduction. These results show that both acute and chronic alteration in the Ang-(1-7)-Mas receptor axis may lead to important changes in the autonomic control of circulation, impacting either sympathetic and (or) parasympathetic systems.

Estrogen-dependent effects on behavior, lipid-profile, and glycemic index of ovariectomized rats subjected to chronic restraint stress.

Stress has been shown to negatively affect the immune system, alter the body's metabolism, and play a strong role in the development of mood disorders. These effects are mainly driven through the release of hormones from the hypothalamic-pituitary-adrenal axis (HPA). Additionally, women are more likely to be affected by stress due to the estrogen fluctuation associated with their menstrual cycle. This study aims to evaluate the effect of chronic restraint stress, applied for 30 days, and estrogen replacement on behavior, glucose level, and the lipid profile of ovariectomized rats. Our results suggest that stress increases sweet food consumption in OVX females treated with estradiol (E2), but reduces consumption in animals not treated. Furthermore, stress increases locomotor activity and anxiety as assessed by the Open Field test and in the Elevated Plus Maze. Similarly, our results suggest that E2 increases anxiety in female rats under the same behavioral tests. In addition, stress reduces glucose and TC levels. Moreover, stress increase TG levels in the presence of E2 and decrease in its absence, as well as the estradiol increase TG levels in stressed groups and reduced in non-stressed groups. Our data suggest an important interaction between stress and estrogen, showing that hormonal status can induce changes in the animal's response to stress.